The invention relates to a digital printing device for the dynamic printing of a statically printed substrate web and a reel-fed printing press with such a digital printing device.
Reel-fed printing presses have a plurality of printing units for the static printing of at least one substrate web surface of at least one substrate web with a print image that is the same or print copies, and thus, static. Each print copy in this case typically comprises a plurality of printing pages. Such printing units, which serve for the static printing of the or each substrate web are typically embodied as offset printing units. It is likewise possible that such printing units are embodied as gravure printing units.
In reel-fed printing presses known from the prior art it is already usual to provide at least one digital printing device in addition to the printing units, which serve for the static printing of the or each substrate web with a print image that is the same for all print copies, in order to individualize the print copies through dynamic printing. Such a digital printing device for the dynamic printing preferentially is an inkjet printing device, with the help of which at least one substrate web surface of at least one substrate web can be printed with a print image that is variable for at least some print copies, i.e. printed dynamically.
A reel-fed printing press with a digital printing device for the dynamic printing of a statically printed substrate web in the line for the static printing in the reel-fed printing press is known, for example, from German Patent Document No. DE 10 2007 028 454 A1 and from German Patent Document No. DE 10 2007 028 452 A1.
It is known furthermore from the prior art that a digital printing device for the dynamic printing of an already statically printed substrate web comprises at least one digital printing head preferentially embodied as an inkjet printing head, wherein the digital printing head together with a position sensor is relocateably mounted on a cross member transversely to the transport direction of the substrate web. With the help of the position sensor, the substrate web to be dynamically printed can be measured in order to determine the print position for the dynamic printing of the substrate web with regard to a control.
Although the individualization of statically printed substrate webs with dynamic impressions is already known in principle, the integration of a digital printing device for the dynamic printing in a reel-fed printing press poses difficulties, in particular it is not ensured to date that the dynamic printing of a statically printed substrate web can be carried out in line with the static printing in the reel-fed printing press in a user-friendly manner with little effort.
Starting out from this, the object of the present invention is to create a new type of digital printing device for the dynamic printing of a statically printed substrate web and a reel-fed printing press with such a digital printing device.
According to the invention, the digital printing device can be provided with a signal via an interface from a signal source of the reel-fed printing press, which at least comprises a speed signal of the reel-fed printing press and a cylinder trigger signal of the reel-fed printing press, wherein a position sensor control dependent on the cylinder trigger signal and on measurement values of the or each position sensor generates a synchronization signal for the digital printing device out of the cylinder trigger signal, making it available to a digital printing head control, wherein a speed signal transformer dependent on the speed signal and a predetermined dynamic print resolution generates a feed signal for the digital printing device out of the speed signal, making it available to the digital printing head control, and wherein the digital printing head control activates the or each digital printing head as a function of the synchronization signal and as a function of the feed signal.
With the invention it is provided to exclusively connect the digital printing device via a signal source of the reel-fed printing press with respect to data which are time-critical to the dynamic printing. Thus, the signal source of the reel-fed printing press provides the digital printing device with a signal, which on the one hand comprises a speed signal of the reel-fed printing press and on the other hand a cylinder trigger signal of the reel-fed printing press.
Dependent on the cylinder trigger signal and on measurement values of the or each position sensor, the position sensor control determines the synchronization signal for the digital printing device out of the cylinder trigger signal, making this synchronization signal available to the digital printing head control.
Dependent on the speed signal of the reel-fed printing press and the predetermined dynamic print resolution, the speed signal transformer determines the feed signal for the digital printing device for the dynamic printing out of the speed signal of the reel-fed printing press, making it available to the digital printing head control.
Based on the synchronization signal and the feed signal, the digital printing head control activates the or each digital printing head in order to dynamically print the respective substrate web in addition to the static printing of the substrate web in the reel-fed printing press in line and because of this to be able to also carry out individualizations of print copies.
Furthermore, the maximum print speeds of the dynamic printing and of the static printing can be limited and matched to one another through a data comparison with a predetermined print resolution for the dynamic printing. The data comparison is carried out at least between the speed signal of the reel-fed printing press and the feed signal for the digital printing device.
The system architecture of the digital printing device according to the invention for the dynamic printing of a statically printed substrate web in line in the reel-fed printing press allows in a user-friendly way the individualization of statically printed substrates with a dynamic impression.
Preferentially, the signal source of the reel-fed printing press, the or each position sensor, the position sensor control, the speed signal transformer, the digital printing head control and the or each digital printing head for the dynamic printing exchange time-critical data preferentially as hardware signals.
The or each position sensor, the position sensor control, the speed signal transformer, the digital printing head control and an operator interface additionally exchange non-time-critical data preferentially as network signals for the dynamic printing by way of a data network.
The data exchange of the time-critical data for the dynamic printing by way of hardware signals and the data exchange of the non-time-critical data for the dynamic printing as network signals is particularly preferred and allows a simple integration of the digital printing device for the dynamic printing in the reel-fed printing press.
No intervention in existing control systems of the reel-fed printing press is required in order to integrate a digital printing device for the dynamic printing in a reel-fed printing press.
According to an advantageous further development of the invention, the digital printing device for the dynamic printing can be provided with the signal, which comprises the speed signal and the cylinder trigger signal from the single signal source of the reel-fed printing press, wherein the single signal source of the reel-fed printing press is either a central pickup of the reel-fed printing press or an encoder of the reel-fed printing press. A central pickup is present in all reel-fed printing presses known from practice and can provide the signal, which comprises the speed signal and the cylinder trigger signal, to the digital printing device for the dynamic printing without further hardware effort. Alternatively, the signal can be provided by an encoder, which is assigned to a printing press cylinder.
Preferred further developments of the invention are obtained from the following description. An exemplary embodiment of the invention is explained in more detail by the drawings without being restricted thereto